Comparator gauge



c. B. MOORE 2,374,154

COMPARATOR GAUGE Filed May 14, 1942 s sheets-$11541 1 April 17, 1945.

Nm. QW

hw. (mh

mw. Anw

mm. mw

April 17, 1945. c. B. MOORE COMPARATOR GAUGE Filed May 14, 1942 5Sheets-Sheet 2 April 17, 1945. c. B. MOORE COMPARATOR GAUGE Filed May14, 1942 3 Sheets-Sheet 5 provide a comparator Patented Apr. 1"?, 1945l' UNITED STATES COMPARATOR GAUGE Coleman B. Moore,

Moore lroduct's Co., partnership Carroll Park, Pa..

assignor to Philadelphia, Pa., a oo- Appucauon May 14,'1a4z. serian No.442,953 17' claims." (ci. sri-17s) This invention relates to comparatorgauges, and more particularly to a pneumatic gauge for recordingdimensions, and which isadapted for a variety of purposes.

Dimension gauges heretofore available have not 5 been equipped formaking an accurate andpermanent record of readings, particularly wherethe work has an internal bore of substantial length to be gauged.

It is the principal object of the present invention to provide animproved comparator gauge with which a record may be readily made of diymensions at a succession of locations.

It is a further object of the present invention to provide a comparatorgauge which is particularly suited for gauging internal bores at aplurality of locations along the bore and recording the dimensions atthe respective locations.

It is a further object of the present invention to gauge in which apressure is transmitted which is directly proportional to a particulardimension.

It is a further object of the present invention to provide a comparatorgauge by which a permanent record of dimensions maybe made and withwhich a comparison with master gauges may be incorporated on the record.

Other objects of the invention will be apparent from the annexedspecication and claims.

'I'he nature and characteristic features of the 30 invention will bemore readily understood from the following description, taken inconnection with the accompanying drawings forming part hereof, in whichFigure 1 is a diagrammatic view of a com- 35v parator gauges inaccordance vention;

Fig. 2 is a fragmentary vertical central sectional view through aportion of the transmitter head:

Fig. 3 is a fragmentary horizontal plan view of a portion of Fig. 2showing the ,follower roller and the mounting therefor; y

Fig. 4 is an enlarged transverse vertical sectional view takenapproximately on the line 4 4v 45 of Fig. 2; y

Fig. 5` is a fragmentary view partly in section and partly in elevationof a recorder for use in connection with the present invention; and

Fig. 6 is a horizontal sectional view taken ap- 50 proximately on theline 6-6 of Fig. 5. f

It will, of course, be understood that the description and drawingsherein are illustrative merely, and that various modifications andchanges may be made inl the structure .disclosedC 55 with the presentinconsisting of lower without departing from the spirit of theinvention. y

Referring more particularlyto Fig. 1 of the drawings, a preferredembodiment of the invention is illustrated diagrammatically. One form ofwork for which the gauge is particularly adapted shown at I0, andconsists-of along tube having an internal bore Il, which is to bemeasured. Although the work I0 is illustrated as greatly reduced inlength, it may have a length of the order of a hundred or more times thediameter ofthe internal bore I I.

The gauge includes a transmitterhead I2 havf .ing a pressure transmittertherein, hereinafter described in detail. The transmitter head I2 has aforward guide and support I4, and a guide and support I5 of anypreferred character to function at the innermost end of the work, suchfor example, as spaced rings on the periphery and of suilicientlysmaller diameter than that of the work so as not to jam or bind. Thetransmitter head I2 is preferably provided intermediate its ends with atwo point support at the lower part supporting rollers I6. An uppermovable roller I1 is provided.and constitutes a gauge roller to followthe internal surface of the work to be gauged and is movable ashereinafter pointed out. y The transmitter head I2 is mounted by meansof a flexible connection 22, on the end of a rigidv extension tube I8,suitably marked in inches ort other desired divisions as at I 9, inaccordance with the length of the work to be gauged and the character ofrecord desired. A limit disc 23 is provided so that misalinement of theextension tube I8 is not transferred to the transmitter head I2 but istaken up by the flexible connection 22. A limit stop 20 may be providedat the outer end of the extension tube I8 to limit the extent ofinsertion of the transmitter head I2 within the work.

An air compressor or other suitable source of pressure uid is provided..connected to a receiver 25, and a. delivery line 26 is connected fromthe receiver 25 to a lter and drip well 21 for filtering the pressureiluid and removing moisture and vdirt therefrom. A manual shut-oil valve28 may befprovided in the delivery line 26.

A transmitter supply line 30 is connected to the outlet side of the lter21, and auid pressure regulator JI is connected in the transmittersupply line 30 for maintaining a. pressure regulated supply of uid. fordelivery through the y transmitter supply pipe l0, and through theinterior of the extension tube I8 to the transmitter head I2. A pressuregauge 32 may be provided in the transmitter supply pipe 30 forindicating the pressure of the fluid therein.

A recorder indexing supply pipe 33 is provided, and is connected to theoutlet side of the filter 21, A iiuid pressure regulator 34 is connectedin the supply pipe 33 for maintaining a pressure regulated supply of uidfor delivery through the supply pipe 33. The pressure regulator 34 maybe adjusted for the same delivered pressure as the pressure regulator3l, or for some other predetermined pressure, and a pressure gauge 35may be provided in the supply pipe 33 for indicating the pressure of theiluid therein.

The supply pipe 33 is connected through an orice or other restriction 36to a branch connection or T 31, from one branch of which a pipe 3B isconnected to a recorder 40, and to the other branch of which a pipe 4Iis connected.

An indexing release valve 4Z is provided on thc end of the pipe 4I formanual release of the pressure in the pipes 39 and 4I, and on thedischarge side of the orifice 3E, in the manner and for purposeshereinafter explained. The recorder 40 also has a pipe 43 connectedthereto for the delivery of pressure iiuid from the .pressuretransmitter in the transmitter head i2 and through the interior of theextension tube i 8. An indicator 44 may also be connected to the DiDe 43for visible or audible indication.

In Figs. 2., 3 and 4, certain details of structure of the transmitterhead l2 are illustrated, parts which are not requisite to anunderstanding of the operation having been omtted. As indicated above,the transmitter head I2 has a gauge roller I1 mounted therein, the gaugeroller I1 preferably being carried on a spindle 45 mounted on a leverarm 46. The lever arm 46 is mounted on alined spindles 41 carried in xedportions I2a of the transmitter head i2. The lower end of the lever arm45 has a contact member 48 for engagement with an actuator rod 49slidable within another fixed portion 12b of the transmtter head I2. Thedistance between the contact member 48 and the gauge roller I1 ispreferably greater than the distance between the gauge roller I1 and thespindle 41 for magnification of the variation in positioning of thegauge roller I1.

The actuator rod 49 is supported in any desired manner such as by aguide i2. The actuator rod 49 has a flange 58 thereon` and a spring 5|is interposed between the fixed portion l2 and the ange 50 for impartinga bias to the rod 49, and therefrom through the contact member 48, andthe lever arm 46 to the gauge roller i1.

The pressure transmitter in the transmitter head I2 may be of anydesired type, but is preferably of the follow-up or rebalancing type,and includes flexible metallic bellows 55 and iiexible metallic bellows55 secured in fluid-tight relationship to and on opposite sides of aixed portion I2e of the transmitter head I2. The bellows 55 is closed atthe other end by a plate 51 secured to the bellows 55 in huid-tightrelationship. and the bellows 56 is closed at its other end by a. plate58 secured thereto in fluid-tight relationship. The bellows 55 and 58have the same internal area so that variations in the supply pressureacting therein are compensated. A spring 60 having linear expansioncharacteristics is provided between the bellows plate B and the'forwardend of the iixed portion I2f. A washer 59 may be interposed between theend of the spring 60 and the portion |2, and washers 59 of differentthicknesses may be employed for shifting the zero of the transmittedpressure. A casing 6l is secured to the iixed portion I2 of thetransmitter head I2, and encloses the bellows to provide a fluidpressure chamber 82. A bore 63 in the xed portion i2e is incommunication with this chamber through an opening 64, and the pipe 43is connected thereto.

The end 65 oi the casing El serves as a limit stop for the bellows plate51 in one direction, and a sleeve 66 serves as a limit stop in the otherdirection.

The bellows plates 51 and 58 are spaced by a connector 61, which issecured at its forward end to the bellows plate 51, extends through anopening 58 in the iixed portion l2e, and is secured at its rear end tothe bellows plate 58, in fiuidtight relationship. A iluld pressurechamber 10 is thus provided within the bellows 55 and the bellows 56,and a bore 1I in the fixed portion 12e is in communication with thischamber 1U. The line 38 is connected to the bore 1i.v The connector 61is open at its forward end adjacent the bellows plate 51 and incommunication with the chamber 62, and is in communicaton throughopenings 13 with the chamber 12. The rear end of the connector 61carries an exhaust seat member 15, having a head 16, and threaded intothe connector 61. The pilot valve chamber 12, in the connector 61, has aforward Valve seat 18. The inner end of the exhaust seat member 15 has arear valve seat 19 spaced from the forward valve seat 1B. A pilot valve80 is mounted within the pilot valve chamber 12 for alternativeengagement with one or the other of said seats 18 and 19, or forpositioning therebetween as hereinafter pointed out. The pilot valve 80has an actuator stem 8l which extends through an opening 82 in the plug15 and through the head 1-6. The opening 82 within a portion of the plug15 is larger than the stem 8l to permit the discharge of pressure uidtherealong, and through a discharge opening 83 in the head 16 incommunicat'on with the atmosphere, when the pilot valve 80 is moved awayfrom the rear valve seat 19.

The pilot valve 80 also has a guide stem 84 for longitudinal movement ina guide bore in the connector 61. The portion of the guide bore adjacentthe forward valve seat 18 is enlarged as at 85, and the ports 11 extendbetween this enlargement 85 and the space 1li within the bellows 55 and56. A spring 86 normally tends to move the pilot valve 80 intoengagement with the seat 19.

Upon movement of the pilot valve 80 towards the left, the delivery offluid from the chamber 10, through the bore 11 and the enlargement 85 tothe pilot valve chamber 12, is cut oi or reduced by the positioning ofthe pilot valve 89 with respect to the forward valve seat 19. Thismovement of the pilot valve 88 likewise opens or increases the spacingof the pilot valve 88 with respect to the rear valve seat 18 so that uidis permitted to escape through the bore 82 and the opening 83 from thepilot valve chamber 12. A discharge vent |28 may be provided incommunication with the atmosphere. The controlled discharge of fluid bythe pilot valve 88 under these conditions also permits the discharge offluid from the chamber 62, and the pressure in the chamber 82 isreduced. The reduction in pressure in the chamber 62 decreases the forcetending to move the bellows unit including the bellows 55 and 56 towardsthe right. The resilient' force exerted by the spring 50, and thebellows 55 and 56, causes the bellows unit to move towards the left andto ed out. The ratchet |03 is urged a. new position with respect to thepilot valve 80. In this new position the forces exerted by the spring 60and the bellows 55 and 56 are balanced against the force exerted by thereduced equilibrium pressure in the chamber 62.

If the pilot valve moves towards the right, the discharge of fluidthrough the bore 82 `and the opening 83 is reduced or shut off, andtheopening between the pilot valve 80 and the valve seat 18 is increased.This positioning of the pilot valve 80 permits increased flow of fluidthrough the bore 11. the enlargement 85, and into the chamber 12. Anincreased pressure is. thus builtup in the chamber 12 and is effectivethrough the open end of the connector 611'and in the chamber 62 formoving the bellows unit towards the right and to a new position withrespect to the pilot valve60. In this new position the forces exerted bythe spring 60 and the bellows 55 and 56 are balanced against the forceexerted by the increased equilibrium pressure in the chamber 62.

It will be noted that the bellows unit, including the bellows 55 and 56and the connector 61, follow the positioning of the pilot valve 80 inwhichever direction thepilot' valve 80 is moved. This follow-up actionoccurs quickly and does not require any substantial interval of time.

The movement of the pilot valve 80 may be made very small and of theorder of a few thousandths of an inch, and this movement and the size ofthe ports controlled by the pilot valve 80 may be varied asdesired toobtain a suitable speed of response in transmission to the recorder 40and the indicator 44.

The equilibrium or rebalancing pressure within the chamber 62 isavailable for transmission through the opening 64, the bore 63 and thepipe 43 to the recorder 4|) andthe indicator 44 and is quickly achieved.

In Figs. Sand 6, certain details of the recorderv 40 are illustrated,parts not requisite to an underf standing of the invention having beenomitted.v

The recorder 40 includes'the customary spindle 90 upon which a'chart 9|is mounted for movement upon rotation of the spindle 90. The spindle 90is preferably actuated with a controlled step by step movement, and forlthis purpose, a casing 92 is provided to which the pipe 38 is connected.The casing 92I preferably has a flexible metallic bellows 93 therein,lthe bellows 93 being connected at itsupper end in Huid-tightrelationship to a supporting plate 94 and closed 'at its lower end 95.

wardly therefrom with stop nuts carried therein. The bellows III issecured to the end of the casing H0 in fluid-tight relationship, and

its other end closed by a plate H2 to provide a.l

pressure chamber H3, within the casing I I0, and outside the bellows III. The pipe 43 is connected to the chamber I| 3. The bellows closureplate H2 is connected through suitable linkage H4, of any desired type,to a pen arm H5 having a pen H6 thereon for making a line record on thechart 9|. The pen H6 will thus be positioned in accordance with thepressure prevailing in the chamber H3. The chart may be divided in anydesired manner, but in one preferred embodiment the chart 9| and the penmovement are proportioned so that iifty-thousandths of an inch arerepresented by `approximately four and one-half inches of pen travelconsidered radially on the chart.

The mode of operation of the comparator gauge will now be pointed out.

Pressure fluid is supplied by the compressor to the receiver 25 andthrough the supply pipe 26 and the filter 21 to each of the pressureregulators 3| and 34. The fluid supplied through the pipe 30 to thetransmitter head I2 is delivered through the bore 1I to the fluidpressure chamber 10, and through the ports 11 to the enlarge.- ment 85.The delivery of fluid to the pilot valve `chamber 12 is determined bythe positioning of the pilot valve 80 with respect to the forward valveseat 18. The pressure of the fluid in the pilot valve chamber 12 is alsodetermined by the positioning of the pilot valve 80 with respect to therear valve seat 19, since by the latter the discharge of fluid iscontrolled. The pressure effective in the pilot valve chamber 12 is alsoeffective through the bores 13, the hollow' portion of the Y connector61, and the iiuidpressure chamber 62.

The pressure of the fluid in the chamber 62 is also the bore 63,

tive in the chamber H3 is operative for positioning the bellows |I| andthereby the recording 45 pen H6.

A fluid pressure chamber 96 is thus provided outside the bellows 93.Within the extending upthereon. A ratchet plate IOI is provided,pivotally* mounted on the spindle |02, and a ratchet |03 is carried onthe plate I0|. The ratchet plate I0| isconnectedl to-the arm 99 foractuation upon movement of thej bellows 93 as hereinafter pointleasedpressure position and as actuated downwardly by the spring 91.

A casing I I0 is also provided withinthe recorder 40, and a flexiblemetallic'bellows I I is mounted in av clockwise The actuation of thepilot valve is effected by the positioning of the gauge roller i1. Thegauge roller I1 actuates the lever arm`46, and this positions theactuator rod 49, against the force of the spring 5I. The movement ofthel rod 49 is effective on the pilot valve actuator 8| and the' unit;which includes the bellows 55 and 56, the plates 51Y and 58, and theconnector 61 move to ian-equilibrium and balanced'position determined Iby the pressure effective in-the chamber 62.

The chart 9| of the recorder 40 'is preferably advanced in a step bystep ,movement to correspond to the step by step advance of thetransmitted head I2 in accordance with the markings I9 on the extensiontube I8.y The advance of the chart 9| is accomplished ing the index-ingrelease valve 42, advance -a line is drawn on the chart 9| by the penH6, in accordance with the the pen I I6, by the Ipressure in the chamberH8 acting on the bellows I| I. The bellows 93 is normally compressed bythe pressure in the chamber 96, and the ratchet |03 is thus yin aposition to move downwardly in engagement with the ratchet wheel|05'when desired.v The pressure in the pipe 38 and in the 'chamber 96 isreleased to the at- ;nzosphere .by pressingthe indexing release valveUpon the release of the pressure in the chamber 96, the spring 91movesthe arm 89 down- |3 of the reby momentarily pressand upon suchpositioning of wardly, and this movement through the plate |I, and theratchet |03 causes rotation of the ratchet gear |05 through apredetermined angular movement. The movement of the gear |05 iseffective through the spindle |02, the pinion |06, and the gear |01onthe chart spindle 90 for rotating the chart 9| through the desiredangle so that a line is inscribed by the pen 6 on the chart 9| inaccordance with the positioning of the pen H6 by the pressure in thechamber H3.

In the gauging of the work, it is preferable to rst make a record on thechart 5| with master ring gauges using both the maximum and minimum ringgauges. These gauges are successively brought into engagementrespectively with the rollers I6 and thereof. The dimensions ofthesemaster gauges will then be recorded on the chart 9| as a permanentrecord.

The transmitter head 2 is then inserted into the work I 0 a distancecorresponding to one marking I9 on the extension tube I8, and theindexing release valve 42 is operated once. The transmitter head l2 isthen inserted step by step, preferably in accordance with the markingsI9 on the extension tube I8, and the indexing release valve 42 isoperated once at the conclusion of each step of insertion. Thedimensions al, each spaced interval within the bore will thus berecorded on the chart 9|. At the conclusion of the exploratory record,the master ring gauges are then preferably again applied to the rollersI6 and l1, and the record thereof on the chart 9| will thus provide anabsolute check on the measurements throughout the entire length of thebore I The chart 9| with the record thereon may be removed from therecorder 40 and iiled as a full inspection report on the internalmeasurements of the work.

A magnification of the dimensional position of the gauge roller Il isobtained by the use of the pivotal mounting shown and also by the use ofa transmitted pressure.

It will be understood that the gauge 0f the present invention is notlimited to the indicating or recording of internal dimensions. The gaugeroller Il, or similar dimension responsive element in a suitablemounting, could be readily employed for measurement of other deviationsof dimenl sions and for indicating or for recording the same to providea permanent record of the dimensional characteristics of the Work.

Iclaim:

1. In a comparator gauge, a body member, a gauge member mounted on saidbody member and positioned by the dimensions of the Work being gauged,means responsive to the positioning oi' saidA gauge member fortransmitting a gaseous control pressure, an indicator operated by saidcontrol pressure, a dimension recorder having a movable chart over whichsaid indicator is movable, and manually controlled fluid pressureactuated means for advancing said chart,

2. In a dimension gauge, a body member, a gaseous iiuid pressuretransmitter carried by said body member and responsive to dimensionalvariations of the work being gauged, means including an indicatoractuated from said uid pressure transmitter and a chart over which saidindicator is movable for recording said dimensional variations, andfluid pressure operated members for advancing the chart step by step,whereby the dimensional variation is continuously recorded.

3. In a pnuematic dimension gauge, a body member, a gauge member thereonpositioned by the dimensions of the work being gauged, a

gaseous fluid pressure transmitter having a transmitted pressurecontrolling iloating pilot valve actuated by said gauge member, and arecorder having a record chart, said recorder including indicator meansresponsive to gaseous pressure transmitted by said fluid pressuretransmitter and movable over said chart for recording the dlmensions ofthe work on said chart.

4. In a pneumatic dimension gauge, a body member, a movable gauge membercarried thereby and positioned by the dimensions of the work beinggauged, a gaseous fluid pressure transmitter having a transmittedpressure controlling iloating pilot valve actuated by said gauge member,an indicator responsive to gaseous pressure transmitted by saidtransmitter, a recorder having a record chart over which said indicatoroperates, and manually controlled actuating means for advancing saidrecord chart.

5. In a pneumatic dimension gauge, a body member, a movable gauge membercarried by said body member and positioned by the dimensions of the workbeing gauged, a gaseous iluid pressure transmitter having a iloatingpilotk valve for controlling a, transmitted gaseous pressure, said pilotvalve being actuated by movement of said gauge` member, and an indicatorspaced from said body member and responsive to the transmitted gaseouspressure.

6. In a dimension gauge, a gauge member positioned by contact with thework being gauged, an elongated support for said gauge member havingdimension markings longitudinally spaced thereon, a, gaseous fluidpressure transmitter having a movable control portion actuated by saidgauge member, an indicator responsive to the gaseous pressuretransmitted by said pressure transmitter, a recorder having a chart overwhich said indicator is movable, and manually operated 40 positioningmeans for said chart for positioning Y ing a, record chart over whichsaid indicating' the same to correspond to the aforesaid dimensionmarkings.

'7. In a dimension gauge, a body member, a gauge member carried by saidbody member and positioned by contact with the work being gauged, asupport for said gauge member having dimension markings longitudinallyspaced thereon, a gaseous iiuid pressure transmitter actuated by saidgauge member and having a portion movable in response to uid pressureand to the positioning of said gauge member, a recorder having anindicating member responsive to the pressure transmitted by saidpressure transmitter and havmember is movable, and manually controlledpositioning means for said record chart for positioning the same tocorrespond to the aforesaid dimension markings.

8. In a dimension gauge, a body member, a gauge member carried by saidbody member and positioned by contact with the work being gauged, anelongated support extending from said body member having dimensionmarkings longitudinally spaced thereon, a fluid pressure transmitterhaving a movable portion and a iioating pilot valve carried by saidportion and actuated by said gauge member, said movable portion beingpositioned in accordance with the positioning of said pilot valve, andan indicator actuated by the transmitted pressure 9. In a dimensiongauge, a body member, a gauge member carried by said body member andpoistioned by the dimensions of the Work being gauged, and a gaseousfluid pressure transmitter carriedby said body member for transmittingsponsive wall portion,

. and responsive to lmitter carried by a gaseous iluid pressureinaccordance with the positioning of said gauge member, said iiuidpressure transmitter having a gaseous pressure reand a pilot valvecarried by said wall portion and actuated by said gauge member forcontrolling said transmitted pressure.

10. In a dimension gauge, a body member,

a gauge member carried by said body member the dimensions of the -workbeing gauged, and

said body mem-ber for transmitting a gaseous tluid` pressure inaccordance with the positioning of said gauge member, said pressuretransmitter including a. freely movable pilot valve actuated by `saidgauge` member for controlling said transmitted gaseous pressure.

1l. In a pneumatic member, a pivotally mounted` gauge member carried bysaid body member and positioned by contact with the work being gauged, agaseous iiuid pressure. transmitter carried by said body member having afreely movable pilot valve actuated by said gauge member for controllingthe transmission of gaseous duid pressure, a recorder having anindicating member responsive to the fluid pressure transmitted by saidpressure transmitter and having a. record chart on which said indicatingmember is movable, andI selectively operated positioning means for saidrecord chart.

12. In a dimension gauge, a gauge member positioned by contact with thework, an elongated support for said ous iiuid pressure transmitterhaving a movable control portion actuated by said gauge member, arecorder having an indicator responsive to the pressure transmitted bysaid pressure transmitter and a chart on which said indicator ismovable, and manually operated iluid pressure actuated positioning meansfor said recorder for positioning the same to correspond tothe'aforesaid dimension markings.

13. In a dimension gauge, a body member, a'

gauge member carried thereby and positioned by the dimensions of thework being gauged, means responsive to the positioning of said memberfor transmitting a control ting means including an expansibie chamberhaving a movable element and a pilot .valve carried by said movableelement and actuatedby said gauge member for controlling the pressureconditions in said chamber for transmission as the control pressure,said movable element being positioned by pressure in accordance with thepositioning of said pilot valve, by said control pressure, a dimensionrecorder having a movable chart over which said indicator is movable,and manually controlled pressure actuated means for advancing saidchart.

' 14. In a dimension gauge,.a body member. a

a gaseous fluid pressure trans-l gauge member having dimension markingslongitudinally spaced thereon, a gasepressure, said transmitan indicatoroperated dimension sauge, a body gauge member carried indicator. ismovable, andlmanually controlled pressure actuated means for, advancingsaid chart.

15. In a dimension gauge, a body member, a gauge member carried thereby.and positioned by the dimensions of the work being gauged, and meansresponsive tothe positioning of said gauge member for transmitting agaseous control duid pressure, said transmitting means including a'nexpansible chamber, a movable element forming part of said chamber andmovable in response' to changes in gaseous uid pressure in said chamber,a freely movable pilot valve carried by said movable element andactuated by said gauge member for controlling the pressure effective onsaid member in said chamber, and connections for transmitting thepressure a control pressure.

16. In a dimension gauge. a body member, an elongated support for saidbody member, a.v gauge member carried by said body member and positionedbythe dimensions of thel Work being gauged, means responsive to thepositioning of said gauge member for transmitting a gaseous controlfluid pressure, said transmitting means including a chamber in said bodymember, a

in said chamber as movable element forming part of said chamber andmovable in response to changes in gaseous duid pressure in said chamber,a pilot valve car.- ried by said'movable element and actuated' by saidgauge member for controlling the pressure eiective on said member insaid chamberl and` connections extending through said elongated supportfor transmitting the pressure in said chamber as a control pressure.

17. .In a dimension gauge. a body. member, a gauge member carried. byysaid body member. means for transmitting a gaseous control pressure inaccordance with the positicmingof said gauge member, said transmittingmeans including an expansible chamber having a movable portionpositioned by the 4transmitted gaseous pressur in accordance with theposition of said gauge member, and connections for .transmitting thepressure in said chamber as a control pressure.

COLEMAN B. MOORE.

